This application claims the priority of Korean Patent Application No. 2002-22205, filed on Apr. 23, 2002, and Korean Patent Application No. 2002-22700, filed on Apr. 25, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a fluid supplying system for LCD (liquid crystal display) manufacturing equipment, and more particularly, to a wet processing bath for LCD manufacturing equipment and a fluid supplying system including the wet processing bath.
2. Description of the Related Art
Recently, sizes of LCD panels have been becoming larger and resolutions thereof have been becoming higher. As technical problems concerning, e.g., higher contrast, wider viewing angle, etc., are being solved, conventional CRT (Cathode Ray Tube) devices are rapidly being replaced by LCD devices. Particularly, such a trend is accelerated in relation to the development of active matrix type TFT-LCD (Thin Film Transistor Liquid Crystal Display) devices and wider applications thereof. The active matrix type TFT-LCD is characterized in that switching elements called TFT""s are formed in correspondence to each pixel and the pixels are individually controlled.
Generally, glass is used as a substrate material in a process for fabricating transistors formed in correspondence to each pixel of a TFT-LCD device, i.e., a thin film transistor fabrication process. Since the melting point of glass is relatively low, a processing temperature of the thin film transistor fabrication process is limited to the range of 300 to 500xc2x0 C. Further, in order to embody a circuit on the glass substrate, unit processes of a typical semiconductor fabrication process are applied to the thin film transistor fabrication process. Therefore, lots of wet processes using fluid are adapted to the thin film transistor fabrication process. In the wet processes, such as cleaning, stripping, wet etching, or developing, a fluid such as a chemical solution or deionized water is used.
FIG. 1 is a schematic diagram of a conventional fluid supply system used in manufacturing LCD devices.
Referring to FIG. 1, the fluid supplying system includes a plurality of baths 121, 122, 123 having fluid collection units (not shown), a storage tank 130, a pump 140, a fluid supplement unit 150, and pipelines (not shown) for connecting the foregoing elements. Unit process, e.g., cleaning, etching, or developing, is performed in the baths 121, 122, and 123 and is referred to 1st, 2nd, or 3rd process unit in FIG. 1. The baths 121, 122, and 123 are connected to the storage tank 130 and the pump 140 via the pipelines.
Although three baths 121, 122, and 123 are shown in FIG. 1, there is no limit in the number of baths connected to the pump 130. While the size of the storage tank 130 and the arrangement of the baths are determined according to the number of the baths 121, 122, and 123 equipped in the system, the baths 121, 122, and 123 are generally arranged in a structure where minimum pipelines are used so that a loss of pressure or heat of the fluid can be minimized.
The fluid is supplied to the process units 111, 112, and 113 included in the baths via the pump 140, and the used fluid is collected in the baths 121, 122, and 123. The fluid drained from the baths 121, 122, and 123 includes by-products of each process, such as contaminants, etching residuals, or developing residuals. The fluid collected in the baths 121, 122, and 123 is recollected and stored in the storage tank 130 via the pipelines. During this process, some of the residual materials can be filtered.
As shown in FIG. 1, since a single storage tank 130 is used in connection with a plurality of baths 121, 122, and 123, the size of the storage tank 130 should be large in that a huge amount of fluid can be stored therein. Typically, the storage tank 130 may include a heater (not shown). The heater adequately raises the temperature of the fluid so that the unit processes can be performed efficiently in the process units 111, 112, and 113.
The fluid stored in the storage tank 130 is supplied again to the process units 111, 112, and 113 in the baths via the pump 140. The pipelines connecting the pump and the baths 121, 122, and 123 include valves (not shown), filters (not shown), and regulators (not shown). Fluid is supplied from the fluid supplement unit 150 in addition to the storage tank 130. Since the fluid is adhered to the substrates and drained together with the substrates outside the baths 121, 122, and 123 during the processes, the fluid supplement unit 150 supplements the drained fluid. The fluid supplement unit 150 may also include a heater (not shown).
FIG. 2 is a more detailed diagram of the conventional fluid supply system that is applied to cleaning equipment, in which only one bath 221 is represented. FIG. 2 simply and schematically shows the structure of a cleaning unit 211 placed in the bath 221, as well as valves 261, filters 262, regulators 263, and flow meters 264 included in pipelines, and may be different from the structure of a cleaning unit and the arrangements of pipelines used in actual cleaning equipment.
Apparent from FIGS. 1 and 2, the conventional fluid supplying system is characterized in that a bath is provided for each process unit and only one storage tank is used for a plurality of baths. Accordingly, the distance between the baths and the storage tank and that between the pump and baths are fairly long. Thus, the temperature and the pressure of fluid can be lowered while passing through the long pipelines.
Due to the thermal loss in the conventional fluid supplying system, additional costs are required in equipping large-capacity pumps to reduce the thermal loss. Further, it is hard to supply fluid at an optimum temperature. In addition, since a great amount of fluid should be supplied to each bath, a pump having a large capacity is required.
Furthermore, long pipelines are required for connecting each element of the conventional fluid supplying system, and the arrangements of the pipelines and the structure of the system are very complex. For example, numerous connecting elements, such as filers, valves, elbows, reducers, T""s, etc., should be used and be arranged in a complicated manner. Particularly, in a case where the processing fluid is a highly toxic chemical, such as hydrochloric or nitric acid, the connecting elements used in the pipelines are very expensive, and accordingly, the cost and expenses for manufacturing and maintaining the fluid supplying system are increased.
Moreover, in the conventional fluid supplying system, the amount of fluid supplemented from the fluid supplement unit is very small in comparison to the amount of the fluid used in the process units. If the amount of the processing fluid is great, it is difficult to prevent the gradual increase in the opacity of the fluid even though clean fluid is supplemented from the outside. If the opacity of the fluid increases, the substrates may be contaminated and, thus, the production yield of the LCD devices will be decreased. In order to prevent the contamination of the substrates and the decrease of the production yield, it is required to periodically replace all of the fluid stored in the storage tank with fresh fluid.
Meanwhile, the body of the bath 221 used in the fluid supplying system is generally made of durable materials such as steel, namely, SUS metal or Polyvinyl Chloride (PVC), through welding or coupling since wet processes should be performed to remove organic or inorganic substances, metal ion surface films, corpuscles, or contaminants adhered on the surface of the LCD device.
In order to reduce the process time, the concentration of the chemical fluid used in the wet processes for manufacturing the LCD devices is becoming higher. However, due to the high concentration of the chemical fluid, the surface of the body of the bath 221 is easily damaged.
For example, in a case where the material of the body of bath 221 is steel, namely, as SUS metal, the body of the bath 221 is eroded by a strong acid fluid used in an wet etching process. Thus, the SUS metal is hardly used in the bath for etching process. Further, in a case where the material of the body of bath 221 is PVC, the body of the bath 221 is eroded by an organic solvent used in a stripping process. Since the body of the bath can be melted due to the organic solvent, the use of PVC is also restricted.
That is, the baths used for stripping, cleaning, etching, and developing are not compatible with each other. Further, use of new chemical fluids in the wet processes is restricted because the material of the bath should be firstly considered.
It is an aspect of the present invention to provide a fluid supplying system for LCD manufacturing equipment, which prevents losses of heat and pressure, operates with a small pump, requires lower manufacturing costs and maintenance expenses, and is small in size.
According to the aspect of the present invention, there is provided a fluid supplying system for LCD manufacturing equipment, which includes a bath united with storage tank including a process unit and a fluid storage tank united with the bath; a fluid supplement unit for supplementing fluid that is adhered to substrates within the process unit and discharged together with the substrates outside of the bath united with storage tank; a pump for supplying fluid stored in the bath united with storage tank and the fluid supplemented from the fluid supplement unit; and a plurality of pipelines for connecting the bath united with storage tank, including the process unit, and the fluid supplement unit to the pump. Here, the LCD manufacturing equipment can be cleaning, etching, developing, or stripping equipment.
Preferably, the bath united with storage tank includes a first heater for heating the fluid and the fluid supplement unit includes a second heater for heating the fluid to be supplemented at a constant temperature. Further, the pipelines for connecting the process unit to the pump include filters, valves, regulators, and flow meters.
It is another aspect of the present invention to provide a wet processing bath for LCD manufacturing equipment, which is not significantly influenced by chemical fluid used in wet processes and which can be compatibly used in stripping, cleaning, etching, and developing equipment.
According to another aspect of the present invention, there is provided a wet processing bath for LCD manufacturing equipment, which includes a bath body; a process unit included in the bath body, in which a predetermined process is performed; and an outlet for draining fluid within the bath body outside of the bath, wherein the bath body is made of a durable material and a chemically resistive material is coated on the surface of the durable material. Here, the LCD manufacturing equipment can be cleaning, etching, developing, or stripping equipment.
Preferably, the chemically resistive material is Teflon and may be coated on one side or both sides of the durable material.
According to still another aspect of the present invention, there is provided a fluid supplying system for LCD manufacturing equipment, which includes a bath united with storage tank including a process unit and a fluid storage tank united with the bath; a fluid supplement unit for supplementing fluid that is adhered to substrates within the process unit and drained together with the substrates outside of the bath united with storage tank; a pump for supplying fluid stored in the bath united with storage tank and the fluid supplemented from the fluid supplement unit; and a plurality of pipelines for connecting the bath united with storage tank, including the process unit, and the fluid supplement unit to the pump, wherein the bath united with storage tank includes a bath body; a process unit included in the bath body, in which a predetermined process is performed; and an outlet for draining fluid within the bath body outside of the bath, and the bath body is made of a durable material and a chemically resistive material coated on the surface of the durable material. Here, the LCD manufacturing equipment can be cleaning, etching, developing, or stripping equipment.
Preferably, the bath united with storage tank includes a first heater for heating the fluid and the fluid supplement unit includes a second heater for heating the fluid to be supplemented at a constant temperature. Further, the pipelines for connecting the process unit to the pump include filters, valves, regulators, and flow meters.
It is also preferable that the chemically resistive material is Teflon and that the chemically resistive material is coated on one side or both sides of the durable material.